Device for threading of web-like materials



Sept. 14, 1965 s. WALLIN DEVICE FOR THREADING OF WEB-LIKE MATE RIALS Filed June 19 mm L ML V NW N E V S ATTYS'.

United States Patent Office 3,206,092 Patented Sept. 14, 1965 DEVICE FOR THREADING F WEB-LIKE MATERIALS Sven Wailin, Jonkoping, Sweden, assignor to Aktlebolaget Svenska Fliiktfabriken, Stockholm, Sweden Filed June 19, 1963, Ser. No. 289,467

Claims priority, application Sweden, June 21,1962,

4 Claims. (Cl. 22697) This invention relates to a device for threading a weblike material which is conveyed by air through a drier or a similar treating apparatus, the threading device comprising an endless conveying means running along one side of the conveying path.

When a web-like material is to be treated in driers or similar treating apparatus, it has always proved difficult to guide and transport the leading end of the web, particularly when the material is to be advanced in a plurality of passes arranged above one another. Due to their high conveying speed, driers of modern design do not permit threading by hand. The high speed renders it diflicult to employ the previously known endless rope or belt conveyors running along the side of the conveying path to which the leading end of the web is attached by special fastening means. The difficulties with such driers are especially great when the material to be treated has a low strength, i.e. when the material is either cellulose pulp in a highly wet state or very thin paper and in such cases it proves difiicult to fasten and secure the leading end of the web to the special fastening means.

This invention has a primary object to render possible by simple means an effective and safe threading of weblil-:e material even in such complicated cases as mentioned above.

The invention is characterized by a distribution box for the supply of air under pressure, the box being mounted below the supporting part of the conveying means, in such a manner, that conveying means extends along the entire length of the conveying plane and is located on the same level as the conveying plane. In the preferred embodiment of the invention the distribution box is provided with a number of preferably eye-lid shaped perforations constructed so as to impart to the air emanating therefrom a forward flow direction substantially in parallel with the conveying plane, whereby the leading end of the web-like material, directed somewhat to the side of the conveying plane proper, is fixed in a definite position immediately above the plane of the distribution box and thereby pressed into adhesive engagement with the conveying means, the conveying means thereafter gliding the leading end automatically through the treating apparatus without the need of any fastening means.

The threading device according to the invention is based on the utilizations of a hydrodynamic principle for stabilizing, the hydrodynamic effect resulting because a flow between two surfaces gives rise to a force which draws the surfaces towards one another until the distance therebetween is so small, that the static pressure drop of the fiow maintains equilibrium with the force.

According to the preferred embodiment, the air distribution box is provided on its upper surface with means defining a groove-shaped depression which serves as a guide for the conveying means. The depth of the groove is such that the conveying means projects above the upper plane of the distribution box the distance required for obtaining the desired contact with the web-like material.

The invention is described in greater detail in the fol lowing, reference being had therein to the accompanying drawings showing by way of example an embodiment of a device constructed in accordance with the invention. FIG. 1 is a fragmentary perspective view of a conveying plane in a dryer equipped with a web threading device constructed in accordance with. the invention;

FIG. 2 is a fragmentary enlarged plan view of a section of the threading device illustrated in FIG. 1;

FIG. 3 is an enlarged fragmentary cross section of the threading device taken along line 33 of FIG. 2; and

FIG. 4 is another embodiment of a conveying plane having a threading device constructed in accordance with the present invention.

Referring now to the drawings 1 designates the leading end of a web-like material intended to be advanced over a conveying plane 2 by air supplied through a number of blowing boxes 3 having a perforated upper surface 13. The conveying means includes an endless driven conveyor, which in the embodiment shown in FIG. 2, is a chain 4 mounted to the side of the conveying plane. A distribution box 5 for the supply of air under pressure extends along the entire length of the conveying plane and is provided with a number of perforations 6, which are preferably eye-lid shaped, and constructed so as to impart to the air blown out a forward flow direction substantially parallel with the conveying plane 2. As shown in FIG. 2, the air distribution box 5, according to the preferred embodiment, has on its upper surface a groove-shaped depression 7 which serves as a guide for the conveying means. The groove has a depth which permits the conveying means 4 to project above the upper plane of the air distribution box 5 a sufiicient distance to obtain the desired contact with the web-like material.

The depression serving as a guide for the conveying means may also be provided on the side of the air distribution box facing the blowing boxes, as shown in FIG. 4, in which case the ordinary blowing boxes cooperate with the distribution box for producing the desired effect. In the latter case, the eye-lid shaped perforations are replaced by holes 6a provided in triangular portions 8 pressed out of the upper surface of the distribution box 5a. In order to ensure a substantially horizontal blow direction, the holes are located in a slightly inwardly inclined edge portion 8a of the portions 8.

The threading device may be modified within the scope of the claims, in that two or more chains may be used in combination with the air distribution box as the conveying means.

What I claim is:

1. A device for threading and guiding a web-like material which is to be conveyed air-borne through a drier or the like by a conveying plane, said conveying plane comprising a plurality of blow boxes having a perforated upper surface and adapted to support and convey said material by air passing through said perforated surface, said device including an air distribution box positioned adjacent to said conveying plane and extending along said conveying plane, said air distribution box having a perforated surface adjacent the material to be conveyed, said surface imparting to air emanating from said perforations a forward flow substantially parallel to the upper surface of said blow boxes, whereby air flow from said distribution box causes said web-like material to press towards said surface of said distribution box, conveying means on said distribution box and having a portion coplaner with said conveying plane and adapted to receive and lead the downwardly pressed leading end of the web-like material.

2. A device for threading web-like material in accordance with claim 1 wherein said perforations are substantially eye-lid shaped.

3. A device according to claim 2 including a means References Cited by the Examiner efining a groove shaped depression on said perforated UNITED STATES PATENTS surface extending substantially parallel to said convey- 302 31 ing plane, said depression having a width sufficient to ac- 544,970 8/95 Dodge cornmodate and guide said conveying means and a depth 5 756,600 4/08 98184 X suflicient to permit said conveying means to project above 2,805,898 9/57 W11 Said perforated Sudacg 2,848,820 8/58 Walhn et al. 22697 X 4. A device in accordance with claim 3 wherein said 3,136,539 6/64 Lyman 27126 perforated surface comprises a portion projecting from said distribution box adjacent said conveying means and HENSON WOOD Pr'mary having an inwardly inclined edge portion, said edge por- RAPPAEL M. LUPO, ROBERT B. REEVES,

tion having means defining a hole therein and 'comrnunica- Examiners. tive with at least one of said distribution boxes. 

1. A DEVICE FOR THREADING AND GUIDING A WEB-LIKE MATERIAL WHICH IS TO BE CONVEYED AIR-BORNE THROUGH A DRIER OR THE LIKE BY A CONVEYING PLANE, SAID CONVEYING PLANE COMPRISING A PLURALITY OF BLOW BOXES HAVING A PERFORATED UPPER SURFACE AND ADAPTED TO SUPPORT AND CONVEY SAID MATERIAL BY AIR PASSING THROUGH SAID PERFORATED SURFACE, SAID DEVICE INCLUDING AN AIR DISTRIBUTION BOX POSITIONED ADJACENT TO SAID CONVEYING PLANE AND EXTENDING ALONG SAID CONVEYING PLANE, SAID AIR DISTRIBUTION BOX HAVING A PERFORATED SURFACE ADJACENT THE MATERIAL TO BE CONVEYED, SAID SURFACE IMPARTING TO AIR EMANATING FROM SAID PERFORATIONS A FORWARFD FLOW SUBSTANTIALLY PARALLEL TO THE UPPER SURFACE OF SAID BLOW BOXES, WHEREBY AIR FLOW FROM SAID DISTRIBUTION BOX CAUSES SAID WEB-LIKE MATERIAL TO PRESS TOWARDS SAID SURFACE OF SAID DISTRIBUTION BOX, CONVEYING MEANS ON SAID DISTRIBUTION BOX AND HAVING A PORTION COPLANER WITH SAID CONVEYING PLANE AND ADAPTED TO RECEIVE AND LEAD THE DOWNWARDLY PRESSED LEADING END OF THE WEB-LIKE MATERIAL. 